Answer :
Kelly invested $1,500 in the stock market on January 1
She lost 1/3 of it by the end of January or that is:
(1/3)*1500 = $500
the remaining amount is 1500 - 500 = $1,000
she lost 2/5 of the remaining amount by the end of February:
(2/5)1000 = $400
what is left is: 1000 - 400 = $600.